Numerous articles and materials are packaged in the course of manufacture under special conditions which maintain or prolong their original quality. Surgical devices, for example, are packaged under aseptic conditions or sterilized after packaging as with heat or radiation. Materials subject to oxidation can be packaged under an inert atmosphere such as nitrogen. It is, of course, desirable that such packages retain their integrity in passing from manufacturer to consumer or user. In addition, it is often desirable to insure that products have not been tampered with or adulterated. Thus pharmaceuticals, perfumes, alcoholic beverages and the like may have unique properties associated with well known trademarks, and it is imperative from the manufacturer's point of view to insure that the packaged product has not been opened and the contents diluted or replaced when the consumer purchases the goods. Various guarantees are often dependent on installation by a skilled serviceman, as with sophisticated electronic components, and it is important to provide a means to ascertain whether the component to be installed is in the same condition as when it left the factory.
Various methods of determining package integrity have been devised; see, for example, U.S. Pat. No. 3,221,428 incorporated herein by reference. The device disclosed and claimed therein relies on reagents which react with aim to destroy or discolor an indicator card.
A related indicator device is taught in U.S. Pat. No. 3,093,242. This device uses an ink with an indicator dye sensitive to ethylene oxide to indicate the sterilization of a package by detecting the presence of ethylene oxide in the package. However, no method of indicating whether package integrity is lost after sterilization has been accomplished.